1. Field of the Invention
The present invention relates to injection-molded products fabricated with synthetic resins. More particularly, the present invention relates to a method for fabricating injection-molded products whose exterior design can be diversified and also form structures such as coupling pieces for coupling with a counterpart, i.e. another injection-molded product, on the face where the 3D pattern is formed.
2. Description of the Related Art
In general, the term ‘injection-molded product’ refers to a case or the like having a specific shape, fabricated by melting synthetic resins or plastics and injecting them into a mold. Most goods fabricated with synthetic resins are used in everyday life, including home appliances, portions of mobile phones and/or car interior materials, just to name a few items made by injection molding.
Recently, various kinds of portable electronic devices, including cellular phones, MP3 players, portable multimedia players and portable game consoles, have been become highly-commercialized, and injection-molded products are generally used as external cases for such portable electronic devices. Meanwhile, there is a tendency that with the increasing use of these portable electronic devices, users not only enjoy specific functions of the portable electronic devices, but also the portable electronic devices double as fashion items. Therefore, manufactures of the portable electronic devices are devoting themselves to beautifying and diversifying designs of the devices.
Electronic devices having metallic cases have also appeared as a result of the effort to make the appearance of such devices more fashionable. However, a significant amount of research and development costs, as well as production costs, are required to well develop fashionable covers/appearances for electronic device that address such problems as electric leakage and interference of electromagnetic waves, which occur in electronic devices, and to produce marketable manufactured goods. Therefore, a manufacturing method of forming visual Three-Dimensional (3D) patterns on injection-molded products using an in-mold technology, i.e. a technology of transcribing an ink layer onto the rear face of the injection-molded products, is used to beautify designs of portable electronic devices while minimizing an increase in the costs.
FIG. 1 illustrates a conventional process of forming a 3D pattern by transcribing an ink layer onto the rear face of an injection-molded product 11, and FIG. 2 illustrates a structure in which the injection-molded product 11 with a 3D pattern formed thereon is mounted on an external case 13.
Referring to FIG. 1, in order to form a 3D pattern on the rear face of the injection-molded product 11, the injection-molded product 11 is fabricated by injecting a molten resin after disposing an in-mold film 19 in a mold 21 in which a 3D pattern was already formed in a lattice shape. For a better understanding of the invention, a method of forming a transcription layer on the rear face of the already molded injection-molded product 11 by disposing the in-mold film 19 in the mold 21 has been described in brief in FIG. 1. Actually, however, while the injection-molded product 11 is formed into the mold 21, the 3D pattern in the mold 21 is formed on the rear face of the injection-molded product 11 and the transcription layer by the in-mold film 19 is also formed on the rear face of the injection-molded product 11.
The injection-molded product 11 fabricated through this conventional process is adhered to an external case 13, such as illustrated in FIG. 2. In the manner of adhering the injection-molded product 11 to the external case 13, independent coupling protrusions 17 are formed along sides of the injection-molded product 11 such that the coupling protrusions 17 may be engaged with inner walls of the groove 15 when the injection-molded product 11 is engaged with a groove 15 of the external case 13. A combining or adhering substance, such as a double-faced adhesive tape, may be used to adhere the injection-molded product 11 to the external case 13.
Since the injection-molded product 11 is fabricated after the in-mold film 19 is already disposed in the mold 21, it is impossible to form a structure that provides sufficient force by which the injection-molded product 11 can be engaged with a counterpart, i.e. the external case 13. Therefore, the injection-molded product 11 for external decoration of a portable electronic device cannot be directly fabricated as an external case, and is adhered to the already fabricated external case 13, merely providing a simple decoration effect as a type of decorative veneer constructed via the molding process.
This fabrication method separately fabricates an injection-molded product for decoration, causing an increase in the manufacturing costs. In addition, the separately fabricated injection-molded product is assembled in the external case, resulting in an increase in labor and production time required for the fabrication.